Emerald Ash Borer in Madison: Should You Treat or Remove Your Ash Tree?
That big ash tree in your yard is on borrowed time. The question is what to do about it, and when.
If you have a mature ash tree in your Madison yard, this one is worth reading before the decision gets made for you.
Emerald ash borer, a small invasive beetle, has been working through Dane County's ash trees for years. The choice most homeowners face is not whether it will reach their tree. It is whether to treat that tree or remove it, and waiting too long quietly takes the good options off the table.
What is actually happening to Madison's ash trees
Emerald ash borer was confirmed in Dane County back in 2013, and the scale since then is hard to overstate. The Wisconsin DNR expects it to kill about 99 percent of susceptible ash trees statewide, and more than 90 percent of Dane County's ash are expected to be affected. The county has already lost thousands.
The beetle's larvae tunnel under the bark and cut off the tree's ability to move water and nutrients. An infested tree can look fine for two or three years before the decline becomes obvious, which is exactly what makes it sneak up on people. By the time the canopy is thinning and the woodpeckers show up, the tree has usually been infested for a while.
First, is it even an ash tree?
Plenty of Madison homeowners are not sure what they have, and it matters, because only ash trees are at risk.
Ash have compound leaves, several leaflets arranged along a stem, and branches and buds that grow directly opposite each other rather than staggered. If you are not certain, a certified arborist can tell you in about a minute, and so can the Dane County Tree Board's identification resources. If you have an ash and it connects to the terrace, it is worth knowing who owns it, which we covered in who is responsible for Madison terrace trees.
The treat-or-remove decision
This is the real question, and it comes down to the condition and value of the specific tree.
Treatment can work, and work well, but mostly on the right candidates. A structurally sound tree that has lost less than roughly a third of its canopy is often worth protecting. Treatment means insecticide, usually a trunk injection by a professional that protects the tree for about two to three years, which means it is an ongoing commitment, not a one-time fix. For a healthy, well-placed shade tree, that ongoing cost can still be well worth it.
Removal is the honest answer for a tree that is already in steep decline, structurally compromised, or poorly placed. A dead ash gets brittle and dangerous over time, and removing a large, unstable tree costs more and carries more risk than taking down a stable one. Waiting rarely makes the removal cheaper.
Why waiting costs you
The timing trap is the part most people miss.
Treatment only works while there is a healthy tree left to protect, so the option expires if you wait too long. And removal gets more expensive as the tree declines, because a brittle, unstable ash near a house, a fence, or a power line means more crane time, more care, and more risk. The cheapest, safest version of this decision is almost always the one made earlier rather than later.
What to do now
You do not need to panic, but a mature ash is worth a plan.
Confirm whether you actually have an ash tree. If you do, have a certified arborist assess its health and give you an honest treat-or-remove recommendation for that specific tree. Line up any work in advance rather than in a last-minute rush, when tree services are busiest. And never move ash firewood, since that is one of the main ways the beetle spreads to new areas.
Frequently asked questions
How do I know if my ash tree has emerald ash borer?
Early signs are subtle and easy to miss, thinning at the top of the canopy, D-shaped exit holes, S-shaped tunnels under the bark, and increased woodpecker activity. A certified arborist can assess it more reliably than a glance from the ground.
Is it worth treating, or should I just remove it?
It depends on the tree. A healthy, sound, well-placed ash is often worth treating. A tree in significant decline or a risky spot is usually better removed. An arborist can give you an honest read for your specific tree.
Does treatment ever end?
Not really. Protective trunk injections generally last about two to three years, so treating a tree is an ongoing commitment rather than a one-time cost.
Whose tree is it if it is near the street?
Trees in the terrace, between the sidewalk and the street, are often the city's, which changes who handles them. We broke that down in our terrace tree post.
Can I just leave a dead ash standing?
It is not a good idea. Dead ash become brittle and unpredictable, which makes them more dangerous and more expensive to remove the longer they stand.
Weighing a tree decision on your Madison property?
A big tree is part of what makes a Madison yard feel like home, and these decisions are easier with a clear head and the right people. I am glad to point you toward trusted local certified arborists who can give you an honest assessment.
Read About Madison Terrace Trees
Schedule a Call with Cait
Read the Buyer Guide
General information for Madison-area homeowners. It is not arborist, pest control, or tree care advice. Emerald ash borer facts referenced from the Wisconsin DNR, UW-Madison Extension, and the Dane County Tree Board. For your specific tree, consult a certified arborist.
